1. Field of the Invention
This invention relates generally to semiconductor fabrication, and more particularly to fabricating integrated circuits comprising resistors having different sheet resistances.
2. Description of Background
Integrated circuit designers have been limited to one sheet resistance for the resistors integrated into a particular chip. Further, resistor sheet resistances currently vary significantly across different types of technology. The ability of designers to optimize design layout for increased density has been compromised by these limitations.
Design engineers would be able to better optimize integrated circuit designs if it were practical and economical to integrate resistors of various sheet resistances into a single integrated circuit structure. Design engineers have formed resistors of different materials in an integrated circuit such that the resistors have different sheet resistances. However, such techniques can be costly and time consuming because they utilize multiple deposition, lithography, and/or etch steps to form resistors from different materials.